perplexus.info :: Weights and Scales : Take the right one

Take the right one (Posted on 2013-10-18)

Among 100 coins exactly 4 are fake. All genuine coins weigh the same; all fake coins, too. A fake coin is lighter than a genuine coin.

How would we find at least one genuine coin using two weighings on a balance scale?

Source: 2010 Euler math Olympiad in Russia- authored by A.Shapovalov

No Solution Yet Submitted by Ady TZIDON

Rating: 3.0000 (1 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)

h i n t ,,,,,,partial division

| Comment 13 of 18 |

Divide the set of 100 coins into 3 subsets: 33,33,34.

Try 33 vs 33, explore all possible results and their meaning.

Now, you are on your own.

Posted by Ady TZIDON on 2013-10-20 07:36:28

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